Pilot vane for the aerofoil wings of airplanes



July 12, 1932. H. J. KRATZER PILOT VANE FOR THE AEROFOTL WINGS OFAIRPLANES Filed June 15, 19,29

Patented July 12,1932 I i UNITED STATES PATENT- OFFICE HERBERT J.KRATZER, OF "ST. LOUIS, MISSOURI PILOT VANE FOR T HE AEROFOIL WINGS FAIRPLANES Application filed .Iune 15, 1929. Serial No. 371,113.

This invention relates to an improved pilot Mounted in each wing 2 are aseries of vane for the aerofoil wings of airplanes and spacedlongitudinally disposed ribs 9 each has for its primary object thepurpose of prohaving an extension 10 extending through viding animproved pilot vane which is capand forwardly of the nose 8, the forwardend I s able of cooperating in a manner with the of each extensionproviding a bearing for the U5 wings ofthe plane whereb the loadsustainsupport of respective longitudinal'and horiing ability of thewing sur ace will be greatly zontal disposed alining shafts 11 and 12increased. which are located on each side of the fuse- Another object ofthe invention'is in pfolage 1. p

' viding an improved pilot van'e which will Each shaft 11 is locatedadjacenteach wing I cooperate with the aerofoil wings and inend andwhereas each shaft 12 is located on crease the lift-drift ratio of thewing surface. each sideof the fuselage. and rigidly fixed to 1 A furtherobj ectof the invention is in pro each shaft 11 is an arcuate pilot vanesection viding an improved pilot vane which will 00- 13 and dependedfrom each shaft 11 is a pair i operate with the aerofoil wings tolocatethe of levers 14 each having a connecting rod 15 center of lift inthe center of the wing area. secured thereto which extends to arespective A still further object of the invention is to. operatinglever-16, said operating levers beprovide an airplane with an improvedpilot ing secured to an operating shaft 17. Rigidvane which is disposedin a manner with rely fixed to each shaft 12 is an arcuate pilot spectto the wings of the plane so as to royane section 18 and depended fromeach shaft vide means for changing the efiective li t of 1s a pair ofoperating levers which are similar the wings at a particular speedwithout to the operating levers 14 of the pilot vane changing the angleof incidence. section 13 and connected to each of the de- Still anotherobject of the invention is in pending levers of the shaft 12 is aconnecting 5 providing an airplane with a cooperable forrod 19 each ofwhich. are connected at their/l5 wardly extending pilot vane which willproopposite ends to a respective operating lever vide for the center oflift of the plane re- 20 which are secured to theoperating shaft mainingmore localized in fore and aft po- 21. sitions when the the angle ofincidence of the In the operation of an airplane having this J wings ischanged within practicable limits. improved pilot vane as a part thereofwhich 'ther and further objects will appear in comprises the pilot vanesections 13 and 18, the specification and be specifically pointed as theairplane is moved forward by thrust out in the appended claims,reference being of the propellers 22, the vanes upon being had to theaccompanying drawing, exempliheld in alinement in the position shown infying the invention, and in which Fig. 2 will cause the upwarddeflection of air 35 Figure l is a fragmentary plan view of a stratainto which the nose 8 of the'aerofoil portion of an airplane showingthis improved wings enters and follows, the layerv of air pilot vane asforming a part thereof. designated by the arrow A will be deflectedFigure 2 is a transverse section taken apupwardly between the aliningpilot vane secproximately on the line IIII of Fig. l. 'tions and thenose 8 of the wings and conse- Referring by numerals to theaccompanyquently the air pressure on the leading edge ing drawing 1designates the fuselage of the 7 of the nose Swill be eliminated, Inaddi airplane and extending therefrom on each tion the concave surfaces23 of each pilot side is an aerofoil wing 2, each wing comvane sectionwill cause an upward deflecting prising an upper disposed wing camber 3of an air layer as designated by the arrow and a lower disposed wingcord 4 which are B above the pilot vane and the nose 8 of the spacedfrom one another by the front and wings and the two layers of air asdesignated rear spars 5 and 6 respectively. Disposed by the arrows A andB will provide a strongforwardly of the front spar 5 is the leading ersuction lifting effort of all top areas of the edge 7 of the wing nose 8of each wing. I wing rearwardly with the greatest relative 3 wings willcause a greater partial vacuum to be maintained next above the wingsurface thereby providing a greater lifting effort to the wing.

As the negative pressure is located at the pilot vane sections 13v and18 which is a distance forward of the wings 2 it follows that the centerof the net lift of the wings will be rearward from its present criticalposition as is experienced in the use of thepresent airplane wing.-

In the present type of airplane and in the operationthereof the leadingedge 7 of the nose 8 in flight engages and deflects a strata of airupwardly which results in a downward pressure component on the nose ofthe wing forward of its maximum cross section as indicated by arrow Dand this upwardly deflected air cambering over rearwardly portions ofwing produces its maximum suction effort forward of arrow E which arrowindicates the approximate position of resultant net upward lift.Obviously the lift dueto upwardly deflected air currents is greater thanthe net lift and as the downward component at arrow D is locatedrelatively close to arrow E, it is readily seen that with variations ofspeed and angle of incidence of the plane, the position of net lift doeschange its position critically and to an appreciable extent. When theaerofoil wing as shown is provided with a pilot vane to assume the dutyof causing the upwardly deflected air currents at a position forward ofmain wing structure as indicated by arrow F, it follows that theresultant net lift would be located rearwardly and the distance of thenegative force located at F forwardly of maximum section of the wing isto the distance of the center of lift located at arrow C, rearwardly ofmaximum section approximately as the present distance of center ofnegative force located at arrow D forward of center of maximum section,is to present center of lift located at arrow E rear rearwardly ofmaximum section of wing. The distance from arrow F to arrow C is greaterthan the distance of arrow D to arrow E thus it follows that theposition of the net lift of arrow C would always be more stably locatedunder various flying conditions than would the net lift as heretoforepositioned at arrow E of the aerofoil wing without a pilot vane.

The use of the pilot vane sections 13 and 18 disposed in the manner asshown, forwardly of the nose 8 of=the wings 2, will permit aredistribution of the dead loads such as the necessary landing gear andpower plant 5 and 6 of each wing 2 will provide for mounting the motors25 between the wing spars from which position pusher screws 22 can beactuated. As shown, it is desirable to place the axis 24 of each motorabout which the propellers revolve a distance above each rear wing spar6, as in flight each propeller partially evacuates the space immediatelypreceding it, and will cause an additional suction component whichassists the cambering air strata in sustaining the airplane wing.

With this improved pilot vane disposed forwardly of the wings, theeffective lift of the wings at av particular speed depends upon themagnitude of the upwardly deflected air strata which is principallycaused by the pilot vanes and therefore it follows that the lateralbalance during straight flight of the airplane or the necessary bankingof the plane at turns can be controlled by the simultaneous changing ofthe negative angle of incidence of the end pilot vane sections 13 inopposite Assuming the longitudinal balance requiring a normal negativesetting of the end pilot vane sections 13 and center pilot vane sections18 to approximately five de rees, and should it be desired to elevatethe r1 ht hand wing, the shaft 17 which is coopera le with the righthand pilot vane 13 is operated to a osition wherein the right hand vane13 will Ee moved approximately two degrees more negative or to aposition of approximately seven degrees negative, and simultaneoustherewith the left hand pilot vane 13 is moved by its operating shaft 17to a position of approximately 2 degrees less negative incldence or to aposition of only three degrees negative angle. With the respective pilotvane sections 13 set to these positions, it fol lows that the right wingenters the stronger upward deflected air strata which thus elevates theleftwing due to the respectlve increase and decrease of sustainingability of respective wings. Longitudinal balance does not change withthe momentary changes of setting of the end pilot vane sections 13 astheir average angle of incidence remains the same as the center pilotvane sections 18.

What I claim is 1. In an airplane the combination of an aerofoil wingand a pilot vane having a convexed under surface and a concaved u persurface located forwardly of said wing a ove the wing chord thereof,said pilot vane adapted to cause deflected air strata to cooperate withthe upper contour of said wing.

2. In an airplane the combination of an aerofoil wing and a pilotvanedisposed forwardly thereof, said pilot vane having a convexed lowersurface and a concaved upper directions to one another.

operate with said wing, the end sections of said pilot vane beingseparately operable from the other sections.

- 3. In an airplane the combination of anaerofoil wing and a pivotedpilot vane havin a convexed lower surface and a concave upper surfacedisposed forwardly thereof, said pilot vane being divided: into sectionsand adapted to cause deflectedfair strata to simultaneously cooperatewith'the top and bottom surfaces of said wing.

4. In an airplane, a pilot vane having a convexed lower surface and aconcaved upper surface disposed forwardly of the aerofoil wing and on aplane above the wing chord thereof adapted to load the airplanestructure with an air-load during flight.

5. In an airplane, a pilot'vane having a convexed lower surface and aconcaved upper surface disposed forwardly of the aerofoil wing and on aplane above the wing chord thereof adapted to load the airplanestructure with an adjustableair-load at a point forward of the wingduring flightior trimming the longitudinal stability of the airplane. t

HERBERT J. KRATZER.

